[newlib-cygwin] Cygwin: file I/O: make sure to treat write return value as ssize_t

[Corinna Vinschen <corinna@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=5a7e130c31dfdf78f2e1b30dd6ec39a842be1336

commit 5a7e130c31dfdf78f2e1b30dd6ec39a842be1336
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Fri Apr 24 16:14:43 2020 +0200

    Cygwin: file I/O: make sure to treat write return value as ssize_t
    
    The return type of fhandler write methods is ssize_t.  Don't
    use an int to store the return value, use ssize_t.  Use ptrdiff_t
    for the buffer size.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/fhandler.cc | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index d754077b1..9d6271b3d 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -949,9 +949,9 @@ fhandler_base::write (const void *ptr, size_t len)
 	    }
 
 	  /* We've got a buffer-full, or we're out of data.  Write it out */
-	  int nbytes;
-	  int want = buf_ptr - buf;
-	  if ((nbytes = raw_write (buf, want)) == want)
+	  ssize_t nbytes;
+	  ptrdiff_t want = buf_ptr - buf;
+	  if ((nbytes = raw_write (buf, (size_t) want)) == want)
 	    {
 	      /* Keep track of how much written not counting additional \r's */
 	      res = data - (char *)ptr;